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Message-ID: <20250904031222.40953-3-ziyao@disroot.org>
Date: Thu, 4 Sep 2025 03:12:24 +0000
From: Yao Zi <ziyao@...root.org>
To: Andrew Lunn <andrew+netdev@...n.ch>,
"David S. Miller" <davem@...emloft.net>,
Eric Dumazet <edumazet@...gle.com>,
Jakub Kicinski <kuba@...nel.org>,
Paolo Abeni <pabeni@...hat.com>,
"Russell King (Oracle)" <rmk+kernel@...linux.org.uk>,
Jonas Karlman <jonas@...boo.se>,
David Wu <david.wu@...k-chips.com>,
Chaoyi Chen <chaoyi.chen@...k-chips.com>
Cc: netdev@...r.kernel.org,
linux-arm-kernel@...ts.infradead.org,
linux-kernel@...r.kernel.org,
linux-rockchip@...ts.infradead.org,
Yao Zi <ziyao@...root.org>
Subject: [PATCH net] net: stmmac: dwmac-rk: Ensure clk_phy doesn't contain invalid address
We must set the clk_phy pointer to NULL to indicating it isn't available
if the optional phy clock couldn't be obtained. Otherwise the error code
returned by of_clk_get() could be wrongly taken as an address, causing
invalid pointer dereference when later clk_phy is passed to
clk_prepare_enable().
Fixes: da114122b831 ("net: ethernet: stmmac: dwmac-rk: Make the clk_phy could be used for external phy")
Signed-off-by: Yao Zi <ziyao@...root.org>
---
drivers/net/ethernet/stmicro/stmmac/dwmac-rk.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)
On next-20250903, the fixed commit causes NULL pointer dereference on
Radxa E20C during probe of dwmac-rk, a typical dmesg looks like
[ 0.273324] rk_gmac-dwmac ffbe0000.ethernet: IRQ eth_lpi not found
[ 0.273888] rk_gmac-dwmac ffbe0000.ethernet: IRQ sfty not found
[ 0.274520] rk_gmac-dwmac ffbe0000.ethernet: PTP uses main clock
[ 0.275226] rk_gmac-dwmac ffbe0000.ethernet: clock input or output? (output).
[ 0.275867] rk_gmac-dwmac ffbe0000.ethernet: Can not read property: tx_delay.
[ 0.276491] rk_gmac-dwmac ffbe0000.ethernet: set tx_delay to 0x30
[ 0.277026] rk_gmac-dwmac ffbe0000.ethernet: Can not read property: rx_delay.
[ 0.278086] rk_gmac-dwmac ffbe0000.ethernet: set rx_delay to 0x10
[ 0.278658] rk_gmac-dwmac ffbe0000.ethernet: integrated PHY? (no).
[ 0.279249] Unable to handle kernel paging request at virtual address fffffffffffffffe
[ 0.279948] Mem abort info:
[ 0.280195] ESR = 0x000000096000006
[ 0.280523] EC = 0x25: DABT (current EL), IL = 32 bits
[ 0.280989] SET = 0, FnV = 0
[ 0.281287] EA = 0, S1PTW = 0
[ 0.281574] FSC = 0x06: level 2 translation fault
where the invalid address is just -ENOENT (-2).
diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac-rk.c b/drivers/net/ethernet/stmicro/stmmac/dwmac-rk.c
index cf619a428664..26ec8ae662a6 100644
--- a/drivers/net/ethernet/stmicro/stmmac/dwmac-rk.c
+++ b/drivers/net/ethernet/stmicro/stmmac/dwmac-rk.c
@@ -1414,11 +1414,17 @@ static int rk_gmac_clk_init(struct plat_stmmacenet_data *plat)
if (plat->phy_node) {
bsp_priv->clk_phy = of_clk_get(plat->phy_node, 0);
ret = PTR_ERR_OR_ZERO(bsp_priv->clk_phy);
- /* If it is not integrated_phy, clk_phy is optional */
+ /*
+ * If it is not integrated_phy, clk_phy is optional. But we must
+ * set bsp_priv->clk_phy to NULL if clk_phy isn't proivded, or
+ * the error code could be wrongly taken as an invalid pointer.
+ */
if (bsp_priv->integrated_phy) {
if (ret)
return dev_err_probe(dev, ret, "Cannot get PHY clock\n");
clk_set_rate(bsp_priv->clk_phy, 50000000);
+ } else if (ret) {
+ bsp_priv->clk_phy = NULL;
}
}
--
2.50.1
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